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Humans affect climate on small scale in backyard

Not a day goes by that we don’t hear about the global climate. There is concern that the average temperature of Earth may be changing based on human activities.

Whether or not this is the case, it is true that human activities can affect the climate on a smaller scale.

I found this to be true when flying a small airplane in Kansas, where a freshly plowed section of dark ground just beyond the end of the runway could buffet your wings with the warm air rising off them and make landings quite interesting. This would happen because the sun added heat to the dark-colored dirt more quickly than the surrounding, lighter-colored wheat fields. And as everyone remembers from science class, warm air rises.

I also found this to be true while driving around the Olympic Peninsula of Washington state. Everyone remembers (from geography classes, right?) that it rains a great deal in Washington.

In fact, near the town of Forks, Wash., more than 200 inches of rain fall each year. A large area of the peninsula is actually considered a rain forest. (Did you think all rain forests were tropical?)

But about 90 miles from Forks, Wash., is a town called Sequim, which advertises its climate, too — based on the fact that it receives less than 20 inches of rain a year.

How can a small patch of desert exist less than a hundred miles from a rain forest?

It’s called the “rain shadow” of the Olympic Peninsula. In this area, although the humid air from the Pacific Ocean causes a great deal of rain, the moisture is “squeezed” out of the air in a small area downwind of the highest point of the peninsula.

These areas are called microclimates. We usually think of weather conditions being fairly uniform over large areas, but microclimates are small areas in which weather conditions are consistent, but which may be drastically different than in areas very near them.

What causes them?

They can be caused by nature, as in the case of the Olympic Peninsula rain shadow described above (and other rain shadow areas which exist around the world).

They can also be created by human activity, something as simple as a plowed field at the end of the runway. Cities cause their own “bubbles” of heat, where average temperatures are higher than the surrounding areas.

Some of the most important to me are the ones that exist around my own house. That is because my wife is an avid gardener. I am often honored to help her in her endeavors. My part usually consists of watering the plants and moving heavy pots. I dig holes, too.

But she is also the one who suggested this article be written. She has shown me how microclimates affect an area as small as our downtown lot.

She grows plants that usually don’t do well in Grand Junction. Some flourish in areas south of here, others in colder climates to the north. They work because of how and where she locates them on our property.

The climate of your own yard can be affected by a number of factors. One factor we think of is sunlight and heat. The warmth of a particular location is affected dramatically by the duration of sunlight it “sees” during a day. For example, is something shading the area and, if so, for how long?

It gets more complicated when you consider the time of day and the angle of the sun during the unshaded times (she talks about things like “morning sun” versus “afternoon sun” — my head spins when I try to follow the logic).

Not only that, but is there also a wall nearby that reflects the sunlight, which increases the energy a plant receives and the average ground temperature?

I’ve learned that almost anything you do to your yard or house will affect the microclimate surrounding it. When you consider sunlight, ground slope, soil water retention, wind direction and protection, where your downspouts are located, your soil composition — I’m glad that I just do the watering and pick some weeds.

The duration of snow cover is particularly on my mind right now. I’m wondering how long it will take for the foot of snow in my backyard to leave.

But thanks to what I’ve learned about microclimates, I know where it will stick around the longest.